1
|
Azalim-Neto P, Noël F, Silva SC, Villar JAFP, Barbosa L, O'Doherty GA, Quintas LEM. Simplified Method for Kinetic and Thermodynamic Screening of Cardiotonic Steroids through the K +-Dependent Phosphatase Activity of Na +/K +-ATPase with Chromogenic pNPP Substrate. Mol Pharmacol 2024; 106:225-239. [PMID: 39187390 PMCID: PMC11493336 DOI: 10.1124/molpharm.124.000934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 08/13/2024] [Accepted: 08/15/2024] [Indexed: 08/28/2024] Open
Abstract
The antitumor effect of cardiotonic steroids (CTS) has stimulated the search for new methods to evaluate both kinetic and thermodynamic aspects of their binding to Na+/K+-ATPase (IUBMB Enzyme Nomenclature). We propose a real-time assay based on a chromogenic substrate for phosphatase activity (pNPPase activity), using only two concentrations with an inhibitory progression curve, to obtain the association rate (kon ), dissociation rate (koff ), and equilibrium (Ki ) constants of CTS for the structure-kinetics relationship in drug screening. We show that changing conditions (from ATPase to pNPPase activity) resulted in an increase of Ki of the cardenolides digitoxigenin, essentially due to a reduction of kon In contrast, the Ki of the structurally related bufadienolide bufalin increased much less due to the reduction of its koff partially compensating the decrease of its kon When evaluating the kinetics of 15 natural and semisynthetic CTS, we observed that both kon and koff correlated with Ki (Spearman test), suggesting that differences in potency depend on variations of both kon and koff A rhamnose in C3 of the steroidal nucleus enhanced the inhibitory potency by a reduction of koff rather than an increase of kon Raising the temperature did not alter the koff of digitoxin, generating a ΔH‡ (koff ) of -10.4 ± 4.3 kJ/mol, suggesting a complex dissociation mechanism. Based on a simple and inexpensive methodology, we determined the values of kon , koff , and Ki of the CTS and provided original kinetics and thermodynamics differences between CTS that could help the design of new compounds. SIGNIFICANCE STATEMENT: This study describes a fast, simple, and cost-effective method for the measurement of phosphatase pNPPase activity enabling structure-kinetics relationships of Na+/K+-ATPase inhibitors, which are important compounds due to their antitumor effect and endogenous role. Using 15 compounds, some of them original, this study was able to delineate the kinetics and/or thermodynamics differences due to the type of sugar and lactone ring present in the steroid structure.
Collapse
Affiliation(s)
- Pedro Azalim-Neto
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (P.A.-N., F.N., L.E.M.Q.); Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (S.C.S., J.A.F.P.V.); Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (L.B.); and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (G.A.O.)
| | - François Noël
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (P.A.-N., F.N., L.E.M.Q.); Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (S.C.S., J.A.F.P.V.); Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (L.B.); and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (G.A.O.)
| | - Simone C Silva
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (P.A.-N., F.N., L.E.M.Q.); Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (S.C.S., J.A.F.P.V.); Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (L.B.); and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (G.A.O.)
| | - José A F P Villar
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (P.A.-N., F.N., L.E.M.Q.); Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (S.C.S., J.A.F.P.V.); Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (L.B.); and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (G.A.O.)
| | - Leandro Barbosa
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (P.A.-N., F.N., L.E.M.Q.); Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (S.C.S., J.A.F.P.V.); Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (L.B.); and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (G.A.O.)
| | - George A O'Doherty
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (P.A.-N., F.N., L.E.M.Q.); Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (S.C.S., J.A.F.P.V.); Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (L.B.); and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (G.A.O.)
| | - Luis Eduardo M Quintas
- Laboratório de Farmacologia Bioquímica e Molecular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil (P.A.-N., F.N., L.E.M.Q.); Laboratório de Síntese Orgânica e Nanoestruturas, Universidade Federal de São João del-Rei Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (S.C.S., J.A.F.P.V.); Laboratório de Bioquímica Celular, Universidade Federal de São João del-Rei (UFSJ) Campus Centro-Oeste Dona Lindu, Divinópolis, Brazil (L.B.); and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts (G.A.O.)
| |
Collapse
|
2
|
Awda BJ, Mahoney IV, Pettitt M, Imran M, Katselis GS, Buhr MM. Existence and importance of Na +K +-ATPase in the plasma membrane of boar spermatozoa. Can J Physiol Pharmacol 2024; 102:254-269. [PMID: 38029410 DOI: 10.1139/cjpp-2023-0116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Sodium-potassium-ATPase (Na+K+-ATPase), a target to treat congestive heart failure, is the only known receptor for cardiac glycosides implicated in intracellular signaling and additionally functions enzymatically in ion transport. Spermatozoa need transmembrane ion transport and signaling to fertilize, and Na+K+-ATPase is identified here for the first time in boar spermatozoa. Head plasma membrane (HPM) isolated from boar spermatozoa was confirmed pure by marker enzymes acid and alkaline phosphatase (218 ± 23% and 245 ± 38% enrichment, respectively, versus whole spermatozoa). Western immunoblotting detected α and β subunits (isoforms α1, α3, β1, β2, and β3) in different concentrations in whole spermatozoa and HPM. Immunofluorescence of intact sperm only detected α3 on the post-equatorial exterior membrane; methanol-permeabilized sperm also had α3 post-equatorially and other isoforms on the acrosomal ridge and cap. Mass spectrometry confirmed the presence of all isoforms in HPM. Incubating boar sperm in capacitating media to induce the physiological changes preceding fertilization significantly increased the percentage of capacitated sperm compared to 0 h control (33.0 ± 2.6% vs. 19.2 ± 2.6% capacitated sperm, respectively; p = 0.014) and altered the β2 immunofluorescence pattern. These results demonstrate the presence of Na+K+-ATPase in boar sperm HPM and that it changes during capacitation.
Collapse
Affiliation(s)
- Basim J Awda
- Department of Animal and Poultry Science, University of Guelph, ON, N1G 2W1, Canada
- Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
| | - Ian V Mahoney
- Department of Animal and Poultry Science, University of Guelph, ON, N1G 2W1, Canada
| | - Murray Pettitt
- Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
| | - Muhammad Imran
- Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
- Department of Medicine, Division of Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 2Z4, Canada
| | - George S Katselis
- Department of Medicine, Division of Canadian Centre for Health and Safety in Agriculture, College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 2Z4, Canada
| | - Mary M Buhr
- Department of Animal and Poultry Science, University of Guelph, ON, N1G 2W1, Canada
- Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
| |
Collapse
|
3
|
Feferbaum-Leite S, Santos IA, Grosche VR, da Silva GCD, Jardim ACG. Insights into enterovirus a-71 antiviral development: from natural sources to synthetic nanoparticles. Arch Microbiol 2023; 205:334. [PMID: 37730918 DOI: 10.1007/s00203-023-03660-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/02/2023] [Accepted: 08/14/2023] [Indexed: 09/22/2023]
Abstract
Enteroviruses are pathogens responsible for several diseases, being enterovirus A71 (EVA71) the second leading cause of hand, foot, and mouth disease (HFMD), especially in Asia-Pacific countries. HFMD is mostly common in infants and children, with mild symptoms. However, the disease can result in severe nervous system disorders in children as well as in immunosuppressed adults. The virus is highly contagious, and its transmission occurs via fecal-oral, oropharyngeal secretions, and fomites. The EVA71 burdens the healthy systems and economies around the world, however, up to date, there is no antiviral approved to treat infected individuals and the existent vaccines are not available or approved to be used worldwide. In this context, an extensive literature research was conducted to describe and summarize the recent advances in natural and/or synthetic compounds with antiviral activity against EVA71. The summarized data presented here might simply encourage the future studies in EVA71 antiviral development, by encouraging further research encompassing these compounds or even the application of the techniques and technologies to improve or produce new antiviral molecules.
Collapse
Affiliation(s)
- Shiraz Feferbaum-Leite
- Institute of Biomedical Science (ICBIM), Federal University of Uberlandia (UFU), Uberlandia, Minas Gerais, Brazil
| | - Igor Andrade Santos
- Institute of Biomedical Science (ICBIM), Federal University of Uberlandia (UFU), Uberlandia, Minas Gerais, Brazil
| | - Victória Riquena Grosche
- Institute of Biomedical Science (ICBIM), Federal University of Uberlandia (UFU), Uberlandia, Minas Gerais, Brazil
- Sao Paulo State University, Sao Jose do Rio Preto, Sao Paulo, Brazil
| | | | - Ana Carolina Gomes Jardim
- Institute of Biomedical Science (ICBIM), Federal University of Uberlandia (UFU), Uberlandia, Minas Gerais, Brazil.
- Sao Paulo State University, Sao Jose do Rio Preto, Sao Paulo, Brazil.
| |
Collapse
|
4
|
Wu KX, Yogarajah T, Choy Loe MW, Kaur P, Hua Lee RC, Mok CK, Wong YH, Phuektes P, Yeo LS, Chow VT, Tan YW, Hann Chu JJ. The host-targeting compound peruvoside has a broad-spectrum antiviral activity against positive-sense RNA viruses. Acta Pharm Sin B 2023; 13:2039-2055. [DOI: 10.1016/j.apsb.2023.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/22/2023] [Accepted: 03/02/2023] [Indexed: 03/19/2023] Open
|
5
|
Tiwari S, Rajamanickam G, Unnikrishnan V, Ojaghi M, Kastelic JP, Thundathil JC. Testis-Specific Isoform of Na +-K + ATPase and Regulation of Bull Fertility. Int J Mol Sci 2022; 23:7936. [PMID: 35887284 PMCID: PMC9317330 DOI: 10.3390/ijms23147936] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 12/10/2022] Open
Abstract
An advanced understanding of sperm function is relevant for evidence-based male fertility prediction and addressing male infertility. A standard breeding soundness evaluation (BSE) merely identifies gross abnormalities in bulls, whereas selection based on single nucleotide polymorphisms and genomic estimated breeding values overlooks sub-microscopic differences in sperm. Molecular tools are important for validating genomic selection and advancing knowledge on the regulation of male fertility at an interdisciplinary level. Therefore, research in this field is now focused on developing a combination of in vitro sperm function tests and identifying biomarkers such as sperm proteins with critical roles in fertility. The Na+-K+ ATPase is a ubiquitous transmembrane protein and its α4 isoform (ATP1A4) is exclusively expressed in germ cells and sperm. Furthermore, ATP1A4 is essential for male fertility, as it interacts with signaling molecules in both raft and non-raft fractions of the sperm plasma membrane to regulate capacitation-associated signaling, hyperactivation, sperm-oocyte interactions, and activation. Interestingly, ATP1A4 activity and expression increase during capacitation, challenging the widely accepted dogma of sperm translational quiescence. This review discusses the literature on the role of ATP1A4 during capacitation and fertilization events and its prospective use in improving male fertility prediction.
Collapse
Affiliation(s)
| | | | | | | | | | - Jacob C. Thundathil
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.T.); (G.R.); (V.U.); (M.O.); (J.P.K.)
| |
Collapse
|
6
|
Small Molecule Arranged Thermal Proximity Co aggregation (smarTPCA)-A Novel Approach to Characterize Protein-Protein Interactions in Living Cells by Similar Isothermal Dose-Responses. Int J Mol Sci 2022; 23:ijms23105605. [PMID: 35628420 PMCID: PMC9147192 DOI: 10.3390/ijms23105605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 11/17/2022] Open
Abstract
Chemical biology and the application of small molecules has proven to be a potent perturbation strategy, especially for the functional elucidation of proteins, their networks, and regulators. In recent years, the cellular thermal shift assay (CETSA) and its proteome-wide extension, thermal proteome profiling (TPP), have proven to be effective tools for identifying interactions of small molecules with their target proteins, as well as off-targets in living cells. Here, we asked the question whether isothermal dose-response (ITDR) CETSA can be exploited to characterize secondary effects downstream of the primary binding event, such as changes in post-translational modifications or protein-protein interactions (PPI). By applying ITDR-CETSA to MAPK14 kinase inhibitor treatment of living HL-60 cells, we found similar dose-responses for the direct inhibitor target and its known interaction partners MAPKAPK2 and MAPKAPK3. Extension of the dose-response similarity comparison to the proteome wide level using TPP with compound concentration range (TPP-CCR) revealed not only the known MAPK14 interaction partners MAPKAPK2 and MAPKAPK3, but also the potentially new intracellular interaction partner MYLK. We are confident that dose-dependent small molecule treatment in combination with ITDR-CETSA or TPP-CCR similarity assessment will not only allow discrimination between primary and secondary effects, but will also provide a novel method to study PPI in living cells without perturbation by protein modification, which we named "small molecule arranged thermal proximity coaggregation" (smarTPCA).
Collapse
|
7
|
Pagano E, Elias JE, Schneditz G, Saveljeva S, Holland LM, Borrelli F, Karlsen TH, Kaser A, Kaneider NC. Activation of the GPR35 pathway drives angiogenesis in the tumour microenvironment. Gut 2022; 71:509-520. [PMID: 33758004 PMCID: PMC8862021 DOI: 10.1136/gutjnl-2020-323363] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/10/2021] [Accepted: 03/11/2021] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Primary sclerosing cholangitis (PSC) is in 70% of cases associated with inflammatory bowel disease. The hypermorphic T108M variant of the orphan G protein-coupled receptor GPR35 increases risk for PSC and ulcerative colitis (UC), conditions strongly predisposing for inflammation-associated liver and colon cancer. Lack of GPR35 reduces tumour numbers in mouse models of spontaneous and colitis associated cancer. The tumour microenvironment substantially determines tumour growth, and tumour-associated macrophages are crucial for neovascularisation. We aim to understand the role of the GPR35 pathway in the tumour microenvironment of spontaneous and colitis-associated colon cancers. DESIGN Mice lacking GPR35 on their macrophages underwent models of spontaneous colon cancer or colitis-associated cancer. The role of tumour-associated macrophages was then assessed in biochemical and functional assays. RESULTS Here, we show that GPR35 on macrophages is a potent amplifier of tumour growth by stimulating neoangiogenesis and tumour tissue remodelling. Deletion of Gpr35 in macrophages profoundly reduces tumour growth in inflammation-associated and spontaneous tumour models caused by mutant tumour suppressor adenomatous polyposis coli. Neoangiogenesis and matrix metalloproteinase activity is promoted by GPR35 via Na/K-ATPase-dependent ion pumping and Src activation, and is selectively inhibited by a GPR35-specific pepducin. Supernatants from human inducible-pluripotent-stem-cell derived macrophages carrying the UC and PSC risk variant stimulate tube formation by enhancing the release of angiogenic factors. CONCLUSIONS Activation of the GPR35 pathway promotes tumour growth via two separate routes, by directly augmenting proliferation in epithelial cells that express the receptor, and by coordinating macrophages' ability to create a tumour-permissive environment.
Collapse
Affiliation(s)
- Ester Pagano
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK,Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Joshua E Elias
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK,Division of Gastroenterology and Hepatology, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Georg Schneditz
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK,Norwegian PSC Research Center, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Svetlana Saveljeva
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Lorraine M Holland
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Francesca Borrelli
- Department of Pharmacy, School of Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Tom H Karlsen
- Norwegian PSC Research Center, Oslo University Hospital and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Arthur Kaser
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK,Division of Gastroenterology and Hepatology, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| | - Nicole C Kaneider
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK .,Division of Gastroenterology and Hepatology, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK
| |
Collapse
|
8
|
Marchini M, Ashkin MR, Bellini M, Sun MMG, Workentine ML, Okuyan HM, Krawetz R, Beier F, Rolian C. A Na +/K + ATPase Pump Regulates Chondrocyte Differentiation and Bone Length Variation in Mice. Front Cell Dev Biol 2022; 9:708384. [PMID: 34970538 PMCID: PMC8712571 DOI: 10.3389/fcell.2021.708384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 11/04/2021] [Indexed: 11/23/2022] Open
Abstract
The genetic and developmental mechanisms involved in limb formation are relatively well documented, but how these mechanisms are modulated by changes in chondrocyte physiology to produce differences in limb bone length remains unclear. Here, we used high throughput RNA sequencing (RNAseq) to probe the developmental genetic basis of variation in limb bone length in Longshanks, a mouse model of experimental evolution. We find that increased tibia length in Longshanks is associated with altered expression of a few key endochondral ossification genes such as Npr3, Dlk1, Sox9, and Sfrp1, as well reduced expression of Fxyd2, a facultative subunit of the cell membrane-bound Na+/K+ ATPase pump (NKA). Next, using murine tibia and cell cultures, we show a dynamic role for NKA in chondrocyte differentiation and in bone length regulation. Specifically, we show that pharmacological inhibition of NKA disrupts chondrocyte differentiation, by upregulating expression of mesenchymal stem cell markers (Prrx1, Serpina3n), downregulation of chondrogenesis marker Sox9, and altered expression of extracellular matrix genes (e.g., collagens) associated with proliferative and hypertrophic chondrocytes. Together, Longshanks and in vitro data suggest a broader developmental and evolutionary role of NKA in regulating limb length diversity.
Collapse
Affiliation(s)
- Marta Marchini
- Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada
| | - Mitchell R Ashkin
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Melina Bellini
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Margaret Man-Ger Sun
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Matthew Lloyd Workentine
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Hamza Malik Okuyan
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Roman Krawetz
- Department of Anatomy and Cell Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada
| | - Frank Beier
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Campbell Rolian
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada.,Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| |
Collapse
|
9
|
Otarola G, Hu JC, Athanasiou KA. INTRACELLULAR CALCIUM AND SODIUM MODULATION OF SELF-ASSEMBLED NEOCARTILAGE USING COSTAL CHONDROCYTES. Tissue Eng Part A 2021; 28:595-605. [PMID: 34877888 DOI: 10.1089/ten.tea.2021.0169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ion signaling via Ca2+ and Na+ plays a key role in mechanotransduction and encourages a chondrogenic phenotype and tissue maturation. Here, we propose that the pleiotropic effects of Ca2+ and Na+ modulation can be used to induce maturation and improvement of neocartilage derived from re-differentiated expanded chondrocytes from minipig rib cartilage. Three ion modulators were employed: 1) 4α-phorbol-12,13-didecanoate (4-αPDD), an agonist of the Ca2+-permeable transient receptor potential vanilloid 4 (TRPV4), 2) ouabain, an inhibitor of the Na+/K+ pump, and 3) ionomycin, a Ca2+ ionophore. These ion modulators were used individually or in combination. While no beneficial effects were observed when using combinations of the ion modulators, single treatment of constructs with the three ion modulators resulted in multiple effects in structure-function relationships. The most significant findings were related to ionomycin. Treatment of neocartilage with ionomycin produced 61% and 115% increases in glycosaminoglycan and pyridinoline crosslink content, respectively, compared to the control. Moreover, treatment with this Ca2+ ionophore resulted in a 45% increase of the aggregate modulus, and a 63% increase in the tensile Young's modulus, resulting in aggregate and Young's moduli of 567 kPa and 8.43 MPa, respectively. These results support the use of ion modulation to develop biomimetic neocartilage using expanded re-differentiated costal chondrocytes.
Collapse
Affiliation(s)
- Gaston Otarola
- University of California, Irvine, BME, Irvine, California, United States;
| | - Jerry C Hu
- University of California, Irvine, BME, Irvine, California, United States;
| | | |
Collapse
|
10
|
Ladefoged LK, Schiøtt B, Fedosova NU. Beneficent and Maleficent Effects of Cations on Bufadienolide Binding to Na +,K +-ATPase. J Chem Inf Model 2021; 61:976-986. [PMID: 33502848 DOI: 10.1021/acs.jcim.0c01396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Kinetic properties and crystal structures of the Na+,K+-ATPase in complex with cardiotonic steroids (CTS) revealed significant differences between CTS subfamilies (Laursen et al.). Thus, we found beneficial effects of K+ on bufadienolide binding, which strongly contrasted with the well-known antagonism between K+ and cardenolides. In order to understand this peculiarity of bufalin interactions, we used docking and molecular dynamics simulations of the complexes involving Na+,K+-ATPase, bufadienolides (bufalin, cinobufagin), and ions (K+, Na+, Mg2+). The results revealed that bufadienolide binding is affected by (i) electrostatic attraction of the lactone ring by a cation and (ii) the ability of a cation to stabilize and "shape" the site constituted by transmembrane helices of the α-subunit (αM1-6). The latter effect was due to varying coordination patterns involving amino acid residues from helix bundles αM1-4 and αM5-10. Substituents on the steroid core of a bufadienolide add to and modify the cation effects. The above rationale is fully consistent with the ion effects on the kinetics of Na+,K+-ATPase/bufadienolide interactions.
Collapse
Affiliation(s)
- Lucy Kate Ladefoged
- Department of Biomedicine, Aarhus University, Høegh-Guldbergsgade 10, 8000 Aarhus C, Denmark.,Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Birgit Schiøtt
- Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Natalya U Fedosova
- Department of Biomedicine, Aarhus University, Høegh-Guldbergsgade 10, 8000 Aarhus C, Denmark
| |
Collapse
|
11
|
Vosahlikova M, Roubalova L, Cechova K, Kaufman J, Musil S, Miksik I, Alda M, Svoboda P. Na +/K +-ATPase and lipid peroxidation in forebrain cortex and hippocampus of sleep-deprived rats treated with therapeutic lithium concentration for different periods of time. Prog Neuropsychopharmacol Biol Psychiatry 2020; 102:109953. [PMID: 32360816 DOI: 10.1016/j.pnpbp.2020.109953] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 04/22/2020] [Accepted: 04/27/2020] [Indexed: 12/18/2022]
Abstract
Lithium (Li) is a typical mood stabilizer and the first choice for treatment of bipolar disorder (BD). Despite an extensive clinical use of Li, its mechanisms of action remain widely different and debated. In this work, we studied the time-course of the therapeutic Li effects on ouabain-sensitive Na+/K+-ATPase in forebrain cortex and hippocampus of rats exposed to 3-day sleep deprivation (SD). We also monitored lipid peroxidation as malondialdehyde (MDA) production. In samples of plasma collected from all experimental groups of animals, Li concentrations were followed by ICP-MS. The acute (1 day), short-term (7 days) and chronic (28 days) treatment of rats with Li resulted in large decrease of Na+/K+-ATPase activity in both brain parts. At the same time, SD of control, Li-untreated rats increased Na+/K+-ATPase along with increased production of MDA. The SD-induced increase of Na+/K+-ATPase and MDA was attenuated in Li-treated rats. While SD results in a positive change of Na+/K+-ATPase, the inhibitory effect of Li treatment may be interpreted as a pharmacological mechanism causing a normalization of the stress-induced shift and return the Na+/K+-ATPase back to control level. We conclude that SD alone up-regulates Na+/K+-ATPase together with increased peroxidative damage of lipids. Chronic treatment of rats with Li before SD, protects the brain tissue against this type of damage and decreases Na+/K+-ATPase level back to control level.
Collapse
Affiliation(s)
- Miroslava Vosahlikova
- Laboratory of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lenka Roubalova
- Laboratory of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.
| | - Kristina Cechova
- Laboratory of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic; Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jonas Kaufman
- Laboratory of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Stanislav Musil
- Department of Trace Element Analysis, Institute of Analytical Chemistry of the Czech Academy of Sciences, Brno, Czech Republic
| | - Ivan Miksik
- Laboratory of Translation Metabolism, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Martin Alda
- Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada; National Institute of Mental Health, Klecany, Czech Republic
| | - Petr Svoboda
- Laboratory of Biomathematics, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| |
Collapse
|
12
|
Lyn regulates creatine uptake in an imatinib-resistant CML cell line. Biochim Biophys Acta Gen Subj 2019; 1864:129507. [PMID: 31881245 DOI: 10.1016/j.bbagen.2019.129507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 12/06/2019] [Accepted: 12/22/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND Imatinib mesylate (imatinib) is the first-line treatment for newly diagnosed chronic myeloid leukemia (CML) due to its remarkable hematologic and cytogenetic responses. We previously demonstrated that the imatinib-resistant CML cells (Myl-R) contained elevated Lyn activity and intracellular creatine pools compared to imatinib-sensitive Myl cells. METHODS Stable isotope metabolic labeling, media creatine depletion, and Na+/K+-ATPase inhibitor experiments were performed to investigate the origin of creatine pools in Myl-R cells. Inhibition and shRNA knockdown were performed to investigate the specific role of Lyn in regulating the Na+/K+-ATPase and creatine uptake. RESULTS Inhibition of the Na+/K+-ATPase pump (ouabain, digitoxin), depletion of extracellular creatine or inhibition of Lyn kinase (ponatinib, dasatinib), demonstrated that enhanced creatine accumulation in Myl-R cells was dependent on uptake from the growth media. Creatine uptake was independent of the Na+/creatine symporter (SLC6A8) expression or de novo synthesis. Western blot analyses showed that phosphorylation of the Na+/K+-ATPase on Tyr 10 (Y10), a known regulatory phosphorylation site, correlated with Lyn activity. Overexpression of Lyn in HEK293 cells increased Y10 phosphorylation (pY10) of the Na+/K+-ATPase, whereas Lyn inhibition or shRNA knockdown reduced Na+/K+-ATPase pY10 and decreased creatine accumulation in Myl-R cells. Consistent with enhanced uptake in Myl-R cells, cyclocreatine (Ccr), a cytotoxic creatine analog, caused significant loss of viability in Myl-R compared to Myl cells. CONCLUSIONS These data suggest that Lyn can affect creatine uptake through Lyn-dependent phosphorylation and regulation of the Na+/K+-ATPase pump activity. GENERAL SIGNIFICANCE These studies identify kinase regulation of the Na+/K+-ATPase as pivotal in regulating creatine uptake and energy metabolism in cells.
Collapse
|
13
|
Interaction of ouabain and progesterone on induction of bull sperm capacitation. Theriogenology 2019; 126:191-198. [DOI: 10.1016/j.theriogenology.2018.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 11/06/2018] [Accepted: 12/01/2018] [Indexed: 01/16/2023]
|
14
|
Jing YP, An H, Zhang S, Wang N, Zhou S. Protein kinase C mediates juvenile hormone-dependent phosphorylation of Na +/K +-ATPase to induce ovarian follicular patency for yolk protein uptake. J Biol Chem 2018; 293:20112-20122. [PMID: 30385509 DOI: 10.1074/jbc.ra118.005692] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/11/2018] [Indexed: 12/21/2022] Open
Abstract
In oviparous animals, vitellogenesis is prerequisite to egg production and embryonic growth after oviposition. For successful insect vitellogenesis and oogenesis, vitellogenin (Vg) synthesized in the fat body (homologue to vertebrate liver and adipose tissue) must pass through the intercellular channels, a condition known as patency in the follicular epithelium, to reach the surface of oocytes. This process is controlled by juvenile hormone (JH) in many insect species, but the underlying mechanisms remain elusive. Previous work has suggested the possible involvement of Na+/K+-ATPase in patency initiation, but again, the regulatory cascade of Na+/K+-ATPase for patency initiation has been lacking. Using the migratory locust Locusta migratoria as a model system, we report here that RNAi-mediated knockdown of gene coding for Na+/K+-ATPase, inhibition of its phosphorylation, or suppression of its activity causes loss of patency, resulting in blocked Vg uptake, arrested oocyte maturation, and impaired ovarian growth. JH triggers G protein-coupled receptor (GPCR), receptor tyrosine kinase (RTK), phospholipase C (PLC), inositol trisphosphate receptor (IP3R), and protein kinase C (PKC) to phosphorylate Na+/K+-ATPase α-subunit at amino acid residue Ser8, consequently activating Na+/K+-ATPase for the induction of patency in vitellogenic follicular epithelium. Our results thus point to a previously unidentified mechanism by which JH induces the phosphorylation and activation of Na+/K+-ATPase via a signaling cascade of GPCR, RTK, PLC, IP3R, and PKC. The findings advance our understanding of JH regulation in insect vitellogenesis and oogenesis.
Collapse
Affiliation(s)
- Yu-Pu Jing
- From the Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Hongli An
- From the Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Shanjing Zhang
- From the Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Ningbo Wang
- From the Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Shutang Zhou
- From the Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China.
| |
Collapse
|
15
|
Câmara DR, Kastelic JP, Thundathil JC. Role of the Na +/K +-ATPase ion pump in male reproduction and embryo development. Reprod Fertil Dev 2018; 29:1457-1467. [PMID: 27456939 DOI: 10.1071/rd16091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/19/2016] [Indexed: 12/18/2022] Open
Abstract
Na+/K+-ATPase was one of the first ion pumps studied because of its importance in maintaining osmotic and ionic balances between intracellular and extracellular environments, through the exchange of three Na+ ions out and two K+ ions into a cell. This enzyme, which comprises two main subunits (α and β), with or without an auxiliary polypeptide (γ), can have specific biochemical properties depending on the expression of associated isoforms (α1β1 and/or α2β1) in the cell. In addition to the importance of Na+/K+-ATPase in ensuring the function of many tissues (e.g. brain, heart and kidney), in the reproductive tract this protein is essential for embryo development because of its roles in blastocoel formation and embryo hatching. In the context of male reproduction, the discovery of a very specific subunit (α4), apparently restricted to male germ cells, only expressed after puberty and able to influence sperm function (e.g. motility and capacitation), opened a remarkable field for further investigations regarding sperm biology. Therefore, the present review focuses on the importance of Na+/K+-ATPase on male reproduction and embryo development.
Collapse
Affiliation(s)
- D R Câmara
- Faculdade de Medicina Veterinária, Universidade Federal de Alagoas, Fazenda São Luiz, s/n, Zona Rural do Município de Viçosa, Viçosa-AL, CEP: 57700-000, Brazil
| | - J P Kastelic
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB T2N 4N1, Canada
| | - J C Thundathil
- Department of Production Animal Health, Faculty of Veterinary Medicine, University of Calgary, 3330 Hospital Dr., NW, Calgary, AB T2N 4N1, Canada
| |
Collapse
|
16
|
Bootman MD, Allman S, Rietdorf K, Bultynck G. Deleterious effects of calcium indicators within cells; an inconvenient truth. Cell Calcium 2018; 73:82-87. [DOI: 10.1016/j.ceca.2018.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 01/20/2023]
|
17
|
Samanta P, Wang Y, Fuladi S, Zou J, Li Y, Shen L, Weber C, Khalili-Araghi F. Molecular determination of claudin-15 organization and channel selectivity. J Gen Physiol 2018; 150:949-968. [PMID: 29915162 PMCID: PMC6028499 DOI: 10.1085/jgp.201711868] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 03/08/2018] [Accepted: 05/04/2018] [Indexed: 12/28/2022] Open
Abstract
Members of the claudin family form tight junctions between adjacent epithelial and endothelial cells. Samanta et al. build an atomic model of claudin-15 using molecular dynamics simulations and conclude that four claudin-15 molecules each contribute an aspartic acid residue to form a selectivity filter. Tight junctions are macromolecular structures that traverse the space between adjacent cells in epithelia and endothelia. Members of the claudin family are known to determine tight junction permeability in a charge- and size-selective manner. Here, we use molecular dynamics simulations to build and refine an atomic model of claudin-15 channels and study its transport properties. Our simulations indicate that claudin-15 forms well-defined channels for ions and molecules and otherwise “seals” the paracellular space through hydrophobic interactions. Ionic currents, calculated from simulation trajectories of wild-type as well as mutant channels, reflect in vitro measurements. The simulations suggest that the selectivity filter is formed by a cage of four aspartic acid residues (D55), contributed by four claudin-15 molecules, which creates a negative electrostatic potential to favor cation flux over anion flux. Charge reversal or charge ablation mutations of D55 significantly reduce cation permeability in silico and in vitro, whereas mutations of other negatively charged pore amino acid residues have a significantly smaller impact on channel permeability and selectivity. The simulations also indicate that water and small ions can pass through the channel, but larger cations, such as tetramethylammonium, do not traverse the pore. Thus, our model provides an atomic view of claudin channels, their transport function, and a potential three-dimensional organization of its selectivity filter.
Collapse
Affiliation(s)
| | - Yitang Wang
- Department of Pathology, The University of Chicago, Chicago, IL.,Department of Surgery, The University of Chicago, Chicago, IL
| | - Shadi Fuladi
- Department of Physics, University of Illinois, Chicago, IL
| | - Jinjing Zou
- Department of Pathology, The University of Chicago, Chicago, IL
| | - Ye Li
- Department of Pathology, The University of Chicago, Chicago, IL
| | - Le Shen
- Department of Pathology, The University of Chicago, Chicago, IL .,Department of Surgery, The University of Chicago, Chicago, IL
| | | | | |
Collapse
|
18
|
Abstract
The symmetric tissue and body plans of animals are paradoxically constructed with asymmetric cells. To understand how the yin-yang duality of symmetry and asymmetry are reconciled, we asked whether apical polarity proteins orchestrate the development of the mirror-symmetric zebrafish neural tube by hierarchically modulating apical cell-cell adhesions. We found that apical polarity proteins localize by a pioneer-intermediate-terminal order. Pioneer proteins establish the mirror symmetry of the neural rod by initiating two distinct types of apical adhesions: the parallel apical adhesions (PAAs) cohere cells of parallel orientation and the novel opposing apical adhesions (OAAs) cohere cells of opposing orientation. Subsequently, the intermediate proteins selectively augment the PAAs when the OAAs dissolve by endocytosis. Finally, terminal proteins are required to inflate the neural tube by generating osmotic pressure. Our findings suggest a general mechanism to construct mirror-symmetric tissues: tissue symmetry can be established by organizing asymmetric cells opposingly via adhesions. Apical polarity proteins localize in a pioneer-intermediate-terminal order The orderly localized proteins orchestrate apical adhesion dynamics step by step Apical adhesions assemble asymmetric cells opposingly into a symmetric tissue
Collapse
|
19
|
Bhattacharya K, Bernasconi L, Picard D. Luminescence resonance energy transfer between genetically encoded donor and acceptor for protein-protein interaction studies in the molecular chaperone HSP70/HSP90 complexes. Sci Rep 2018; 8:2801. [PMID: 29434293 PMCID: PMC5809404 DOI: 10.1038/s41598-018-21210-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/31/2018] [Indexed: 12/11/2022] Open
Abstract
Complex patterns of protein-protein interactions (PPInts) are involved in almost all cellular processes. This has stimulated the development of a wide range of methods to characterize PPInts in detail. Methods with fluorescence resonance energy transfer can be technically challenging and suffer from several limitations, which could be overcome by switching to luminescence resonance energy transfer (LRET) with lanthanide ions such as Tb3+. With LRET, energy transfer between PPInt partners works over a larger distance and with less topological constraints; moreover, the long-lived luminescence of lanthanides allows one to bypass the short-lived background fluorescence. We have developed a novel LRET method to investigate PPInts between partners expressed as fusion proteins with genetically encoded donor and acceptor moieties. Upon UV excitation of a tryptophan within a lanthanide binding peptide, the Tb3+ luminescence is harnessed to excite either a green or a red fluorescent protein. We demonstrate the usefulness of the LRET assay by applying it to analyze the interactions of the molecular chaperones HSP70 and HSP90 with their common co-chaperone HOP/Sti1. We recapitulate the previously described interaction specificities between the HSP70/HSP90 C-termini and tetratricopeptide repeat domains of HOP/Sti1 and demonstrate the impact of single point mutants on domain-domain interactions.
Collapse
Affiliation(s)
- Kaushik Bhattacharya
- Département de Biologie Cellulaire, Université de Genève, 30 Quai Ernest-Ansermet, Sciences III, 1211 Genève 4, Switzerland
| | - Lilia Bernasconi
- Département de Biologie Cellulaire, Université de Genève, 30 Quai Ernest-Ansermet, Sciences III, 1211 Genève 4, Switzerland
| | - Didier Picard
- Département de Biologie Cellulaire, Université de Genève, 30 Quai Ernest-Ansermet, Sciences III, 1211 Genève 4, Switzerland.
| |
Collapse
|
20
|
Zoghbi ME, Altenberg GA. Luminescence resonance energy transfer spectroscopy of ATP-binding cassette proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:854-867. [PMID: 28801111 DOI: 10.1016/j.bbamem.2017.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 12/11/2022]
Abstract
The ATP-binding cassette (ABC) superfamily includes regulatory and transport proteins. Most human ABC exporters pump substrates out of cells using energy from ATP hydrolysis. Although major advances have been made toward understanding the molecular mechanism of ABC exporters, there are still many issues unresolved. During the last few years, luminescence resonance energy transfer has been used to detect conformational changes in real time, with atomic resolution, in isolated ABC nucleotide binding domains (NBDs) and full-length ABC exporters. NBDs are particularly interesting because they provide the power stroke for substrate transport. Luminescence resonance energy transfer (LRET) is a spectroscopic technique that can provide dynamic information with atomic-resolution of protein conformational changes under physiological conditions. Using LRET, it has been shown that NBD dimerization, a critical step in ABC proteins catalytic cycle, requires binding of ATP to two nucleotide binding sites. However, hydrolysis at just one of the sites can drive dissociation of the NBD dimer. It was also found that the NBDs of the bacterial ABC exporter MsbA reconstituted in a lipid bilayer membrane and studied at 37°C never separate as much as suggested by crystal structures. This observation stresses the importance of performing structural/functional studies of ABC exporters under physiologic conditions. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.
Collapse
Affiliation(s)
- Maria E Zoghbi
- School of Natural Sciences, University of California, Merced, 4225 N. Hospital Road, Atwater, CA, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79423-6551, USA.
| |
Collapse
|
21
|
|
22
|
Matchkov VV, Krivoi II. Specialized Functional Diversity and Interactions of the Na,K-ATPase. Front Physiol 2016; 7:179. [PMID: 27252653 PMCID: PMC4879863 DOI: 10.3389/fphys.2016.00179] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/04/2016] [Indexed: 12/22/2022] Open
Abstract
Na,K-ATPase is a protein ubiquitously expressed in the plasma membrane of all animal cells and vitally essential for their functions. A specialized functional diversity of the Na,K-ATPase isozymes is provided by molecular heterogeneity, distinct subcellular localizations, and functional interactions with molecular environment. Studies over the last decades clearly demonstrated complex and isoform-specific reciprocal functional interactions between the Na,K-ATPase and neighboring proteins and lipids. These interactions are enabled by a spatially restricted ion homeostasis, direct protein-protein/lipid interactions, and protein kinase signaling pathways. In addition to its "classical" function in ion translocation, the Na,K-ATPase is now considered as one of the most important signaling molecules in neuronal, epithelial, skeletal, cardiac and vascular tissues. Accordingly, the Na,K-ATPase forms specialized sub-cellular multimolecular microdomains which act as receptors to circulating endogenous cardiotonic steroids (CTS) triggering a number of signaling pathways. Changes in these endogenous cardiotonic steroid levels and initiated signaling responses have significant adaptive values for tissues and whole organisms under numerous physiological and pathophysiological conditions. This review discusses recent progress in the studies of functional interactions between the Na,K-ATPase and molecular microenvironment, the Na,K-ATPase-dependent signaling pathways and their significance for diversity of cell function.
Collapse
Affiliation(s)
| | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University St. Petersburg, Russia
| |
Collapse
|
23
|
The Administration of Levocabastine, a NTS2 Receptor Antagonist, Modifies Na+, K+-ATPase Properties. Neurochem Res 2016; 41:1274-80. [DOI: 10.1007/s11064-015-1823-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 12/28/2015] [Accepted: 12/30/2015] [Indexed: 10/22/2022]
|
24
|
Sutherland JC. Repair-dependent cell radiation survival and transformation: an integrated theory. Phys Med Biol 2015; 59:5073-90. [PMID: 25122036 DOI: 10.1088/0031-9155/59/17/5073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The repair-dependent model of cell radiation survival is extended to include radiation-induced transformations. The probability of transformation is presumed to scale with the number of potentially lethal damages that are repaired in a surviving cell or the interactions of such damages. The theory predicts that at doses corresponding to high survival, the transformation frequency is the sum of simple polynomial functions of dose; linear, quadratic, etc, essentially as described in widely used linear-quadratic expressions. At high doses, corresponding to low survival, the ratio of transformed to surviving cells asymptotically approaches an upper limit. The low dose fundamental- and high dose plateau domains are separated by a downwardly concave transition region. Published transformation data for mammalian cells show the high-dose plateaus predicted by the repair-dependent model for both ultraviolet and ionizing radiation. For the neoplastic transformation experiments that were analyzed, the data can be fit with only the repair-dependent quadratic function. At low doses, the transformation frequency is strictly quadratic, but becomes sigmodial over a wider range of doses. Inclusion of data from the transition region in a traditional linear-quadratic analysis of neoplastic transformation frequency data can exaggerate the magnitude of, or create the appearance of, a linear component. Quantitative analysis of survival and transformation data shows good agreement for ultraviolet radiation; the shapes of the transformation components can be predicted from survival data. For ionizing radiations, both neutrons and x-rays, survival data overestimate the transforming ability for low to moderate doses. The presumed cause of this difference is that, unlike UV photons, a single x-ray or neutron may generate more than one lethal damage in a cell, so the distribution of such damages in the population is not accurately described by Poisson statistics. However, the complete sigmodial dose-response data for neoplastic transformations can be fit using the repair-dependent functions with all parameters determined only from transformation frequency data.
Collapse
|
25
|
Li Z, Langhans SA. Transcriptional regulators of Na,K-ATPase subunits. Front Cell Dev Biol 2015; 3:66. [PMID: 26579519 PMCID: PMC4620432 DOI: 10.3389/fcell.2015.00066] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 10/05/2015] [Indexed: 12/20/2022] Open
Abstract
The Na,K-ATPase classically serves as an ion pump creating an electrochemical gradient across the plasma membrane that is essential for transepithelial transport, nutrient uptake and membrane potential. In addition, Na,K-ATPase also functions as a receptor, a signal transducer and a cell adhesion molecule. With such diverse roles, it is understandable that the Na,K-ATPase subunits, the catalytic α-subunit, the β-subunit and the FXYD proteins, are controlled extensively during development and to accommodate physiological needs. The spatial and temporal expression of Na,K-ATPase is partially regulated at the transcriptional level. Numerous transcription factors, hormones, growth factors, lipids, and extracellular stimuli modulate the transcription of the Na,K-ATPase subunits. Moreover, epigenetic mechanisms also contribute to the regulation of Na,K-ATPase expression. With the ever growing knowledge about diseases associated with the malfunction of Na,K-ATPase, this review aims at summarizing the best-characterized transcription regulators that modulate Na,K-ATPase subunit levels. As abnormal expression of Na,K-ATPase subunits has been observed in many carcinoma, we will also discuss transcription factors that are associated with epithelial-mesenchymal transition, a crucial step in the progression of many tumors to malignant disease.
Collapse
Affiliation(s)
- Zhiqin Li
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
| | - Sigrid A Langhans
- Nemours Center for Childhood Cancer Research, Nemours/Alfred I. duPont Hospital for Children Wilmington, DE, USA
| |
Collapse
|
26
|
Quijada-Rodriguez AR, Treberg JR, Weihrauch D. Mechanism of ammonia excretion in the freshwater leech Nephelopsis obscura: characterization of a primitive Rh protein and effects of high environmental ammonia. Am J Physiol Regul Integr Comp Physiol 2015; 309:R692-705. [PMID: 26180186 DOI: 10.1152/ajpregu.00482.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 07/14/2015] [Indexed: 12/23/2022]
Abstract
Remarkably little is known about nitrogenous excretion in freshwater invertebrates. In the current study, the nitrogen excretion mechanism in the carnivorous ribbon leech, Nephelopsis obscura, was investigated. Excretion experiments showed that the ribbon leech is ammonotelic, excreting 166.0 ± 8.6 nmol·grams fresh weight (gFW)(-1)·h(-1) ammonia and 14.7 ± 1.9 nmol·gFW(-1)·h(-1) urea. Exposure to high and low pH hampered and enhanced, respectively, ammonia excretion rates, indicating an acid-linked ammonia trapping mechanism across the skin epithelia. Accordingly, compared with body tissues, the skin exhibited elevated mRNA expression levels of a newly identified Rhesus protein and at least in tendency the Na(+)/K(+)-ATPase. Pharmacological experiments and enzyme assays suggested an ammonia excretion mechanism that involves the V-ATPase, Na(+)/K(+)-ATPase, and carbonic anhydrase, but not necessarily a functional microtubule system. Most importantly, functional expression studies of the identified Rh protein cloned from leech skin tissue revealed an ammonia transport capability of this protein when expressed in yeast. The leech Rh-ammonia transporter (NoRhp) is a member of the primitive Rh protein family, which is a sister group to the common ancestor of vertebrate ammonia-transporting Rh proteins. Exposure to high environmental ammonia (HEA) caused a new adjustment of body ammonia, accompanied with a decrease in NoRhp and Na(+)/K(+)-ATPase mRNA levels, but unaltered ammonia excretion rates. To our knowledge, this is only the second comprehensive study regarding the ammonia excretion mechanisms in a freshwater invertebrate, but our results show that basic processes of ammonia excretion appear to also be comparable to those found in freshwater fish, suggesting an early evolution of ionoregulatory mechanisms in freshwater organisms.
Collapse
Affiliation(s)
| | - Jason R Treberg
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada; and Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada; and
| |
Collapse
|
27
|
Magpusao AN, Omolloh G, Johnson J, Gascón J, Peczuh MW, Fenteany G. Cardiac glycoside activities link Na(+)/K(+) ATPase ion-transport to breast cancer cell migration via correlative SAR. ACS Chem Biol 2015; 10:561-9. [PMID: 25334087 PMCID: PMC4340362 DOI: 10.1021/cb500665r] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
![]()
The cardiac glycosides ouabain and
digitoxin, established Na+/K+ ATPase inhibitors,
were found to inhibit MDA-MB-231
breast cancer cell migration through an unbiased chemical genetics
screen for cell motility. The Na+/K+ ATPase
acts both as an ion-transporter and as a receptor for cardiac glycosides.
To delineate which function is related to breast cancer cell migration,
structure–activity relationship (SAR) profiles of cardiac glycosides
were established at the cellular (cell migration inhibition), molecular
(Na+/K+ ATPase inhibition), and atomic (computational
docking) levels. The SAR of cardiac glycosides and their analogs revealed
a similar profile, a decrease in potency when the parent cardiac glycoside
structure was modified, for each activity investigated. Since assays
were done at the cellular, molecular, and atomic levels, correlation
of SAR profiles across these multiple assays established links between
cellular activity and specific protein–small molecule interactions.
The observed antimigratory effects in breast cancer cells are directly
related to the inhibition of Na+/K+ transport.
Specifically, the orientation of cardiac glycosides at the putative
cation permeation path formed by transmembrane helices αM1–M6
correlates with the Na+ pump activity and cell migration.
Other Na+/K+ ATPase inhibitors that are structurally
distinct from cardiac glycosides also exhibit antimigratory activity,
corroborating the conclusion that the antiport function of Na+/K+ ATPase and not the receptor function is important
for supporting the motility of MDA-MB-231 breast cancer cells. Correlative
SAR can establish new relationships between specific biochemical functions
and higher-level cellular processes, particularly for proteins with
multiple functions and small molecules with unknown or various modes
of action.
Collapse
Affiliation(s)
- Anniefer N. Magpusao
- Department of Chemistry, University of Connecticut, 55 N.
Eagleville Road, U3060, Storrs, Connecticut 06269, United States
| | - George Omolloh
- Department of Chemistry, University of Connecticut, 55 N.
Eagleville Road, U3060, Storrs, Connecticut 06269, United States
| | - Joshua Johnson
- Department of Chemistry, University of Connecticut, 55 N.
Eagleville Road, U3060, Storrs, Connecticut 06269, United States
| | - José Gascón
- Department of Chemistry, University of Connecticut, 55 N.
Eagleville Road, U3060, Storrs, Connecticut 06269, United States
| | - Mark W. Peczuh
- Department of Chemistry, University of Connecticut, 55 N.
Eagleville Road, U3060, Storrs, Connecticut 06269, United States
| | - Gabriel Fenteany
- Department of Chemistry, University of Connecticut, 55 N.
Eagleville Road, U3060, Storrs, Connecticut 06269, United States
| |
Collapse
|
28
|
P2C-Type ATPases and Their Regulation. Mol Neurobiol 2015; 53:1343-1354. [DOI: 10.1007/s12035-014-9076-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 12/29/2014] [Indexed: 12/12/2022]
|
29
|
A structural rearrangement of the Na+/K+-ATPase traps ouabain within the external ion permeation pathway. J Mol Biol 2015; 427:1335-1344. [PMID: 25637661 DOI: 10.1016/j.jmb.2015.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 12/30/2014] [Accepted: 01/18/2015] [Indexed: 02/04/2023]
Abstract
With the use of the energy of ATP hydrolysis, the Na+/K+-ATPase is able to transport across the cell membrane Na+ and K+ against their electrochemical gradients. The enzyme is strongly inhibited by ouabain and its derivatives, some that are therapeutically used for patients with heart failure (cardiotonic steroids). Using lanthanide resonance energy transfer, we trace here the conformational changes occurring on the external side of functional Na+/K+-ATPases induced by the binding of ouabain. Changes in donor/acceptor pair distances are mainly observed within the α subunit of the enzyme. To derive a structural model matching the experimental lanthanide resonance energy transfer distances measured with bound ouabain, we carried out molecular dynamics simulations with energy restraints applied simultaneously using a novel methodology with multiple non-interacting fragments. The restrained simulation, initiated from the X-ray structure of the E2(2K+) state, became strikingly similar to the X-ray structure of the sodium-bound state. The final model shows that ouabain is trapped within the external ion permeation pathway of the pump.
Collapse
|
30
|
Whittaker CAP, Patching SG, Esmann M, Middleton DA. Ligand orientation in a membrane-embedded receptor site revealed by solid-state NMR with paramagnetic relaxation enhancement. Org Biomol Chem 2015; 13:2664-8. [DOI: 10.1039/c4ob02427c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Paramagnetic relaxation-enhanced solid-state NMR reveals a ouabain analogue with an inverted orientation in the Na,K-ATPase inhibitory site.
Collapse
Affiliation(s)
| | | | - Mikael Esmann
- Department of Biomedicine
- Aarhus University
- Aarhus
- Denmark
| | | |
Collapse
|
31
|
Krivoi II. Functional interactions of Na,K-ATPase with molecular environment. Biophysics (Nagoya-shi) 2014. [DOI: 10.1134/s000635091405011x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
|
32
|
Weigand KM, Laursen M, Swarts HGP, Engwerda AHJ, Prüfert C, Sandrock J, Nissen P, Fedosova NU, Russel FGM, Koenderink JB. Na(+),K(+)-ATPase isoform selectivity for digitalis-like compounds is determined by two amino acids in the first extracellular loop. Chem Res Toxicol 2014; 27:2082-92. [PMID: 25361285 DOI: 10.1021/tx500290k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Digitalis-like compounds (DLCs) comprise a diverse group of molecules characterized by a cis-trans-cis ring-fused steroid core linked to a lactone. They have been used in the treatment of different medical problems including heart failure, where their inotropic effect on heart muscle is attributed to potent Na(+),K(+)-ATPase inhibition. Their application as drugs, however, has declined in recent past years due to their small safety margin. Since human Na(+),K(+)-ATPase is represented by four different isoforms expressed in a tissue-specific manner, one of the possibilities to improve the therapeutic index of DLCs is to exploit and amend their isoform selectivity. Here, we aimed to reveal the determinants of selectivity of the ubiquitously expressed α1 isoform and the more restricted α2 isoform toward several well-known DLCs and their hydrogenated forms. Using baculovirus to express various mutants of the α2 isoform, we were able to link residues Met(119) and Ser(124) to differences in affinity between the α1 and α2 isoforms to ouabain, dihydro-ouabain, digoxin, and dihydro-digoxin. We speculate that the interactions between these amino acids and DLCs affect the initial binding of these DLCs. Also, we observed isoform selectivity for DLCs containing no sugar groups.
Collapse
Affiliation(s)
- Karl M Weigand
- Departments of †Pharmacology and Toxicology and ‡Biochemistry, Radboud University Medical Center , P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Katz A, Tal DM, Heller D, Haviv H, Rabah B, Barkana Y, Marcovich AL, Karlish SJD. Digoxin derivatives with enhanced selectivity for the α2 isoform of Na,K-ATPase: effects on intraocular pressure in rabbits. J Biol Chem 2014; 289:21153-62. [PMID: 24917667 DOI: 10.1074/jbc.m114.557629] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the ciliary epithelium of the eye, the pigmented cells express the α1β1 isoform of Na,K-ATPase, whereas the non-pigmented cells express mainly the α2β3 isoform of Na,K-ATPase. In principle, a Na,K-ATPase inhibitor with selectivity for α2 could effectively reduce intraocular pressure with only minimal local and systemic toxicity. Such an inhibitor could be applied topically provided it was sufficiently permeable via the cornea. Previous experiments with recombinant human α1β1, α2β1, and α3β1 isoforms showed that the classical cardiac glycoside, digoxin, is partially α2-selective and also that the trisdigitoxose moiety is responsible for isoform selectivity. This led to a prediction that modification of the third digitoxose might increase α2 selectivity. A series of perhydro-1,4-oxazepine derivatives of digoxin have been synthesized by periodate oxidation and reductive amination using a variety of R-NH2 substituents. Several derivatives show enhanced selectivity for α2 over α1, close to 8-fold in the best case. Effects of topically applied cardiac glycosides on intraocular pressure in rabbits have been assessed by their ability to either prevent or reverse acute intraocular pressure increases induced by 4-aminopyridine or a selective agonist of the A3 adenosine receptor. Two relatively α2-selective digoxin derivatives efficiently normalize the ocular hypertension, by comparison with digoxin, digoxigenin, or ouabain. This observation is consistent with a major role of α2 in aqueous humor production and suggests that, potentially, α2-selective digoxin derivatives could be of interest as novel drugs for control of intraocular pressure.
Collapse
Affiliation(s)
- Adriana Katz
- From the Department of Biological Chemistry, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Daniel M Tal
- From the Department of Biological Chemistry, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Dan Heller
- the Department of Ophthalmology, Asaf Harofeh Hospital, Zerifin 608183, Israel, and
| | - Haim Haviv
- From the Department of Biological Chemistry, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Bilal Rabah
- the Department of Ophthalmology, Kaplan Hospital, Rehovoth 76100, Israel
| | - Yaniv Barkana
- the Department of Ophthalmology, Asaf Harofeh Hospital, Zerifin 608183, Israel, and
| | - Arie L Marcovich
- the Department of Ophthalmology, Kaplan Hospital, Rehovoth 76100, Israel
| | - Steven J D Karlish
- From the Department of Biological Chemistry, Weizmann Institute of Science, Rehovoth 76100, Israel,
| |
Collapse
|
34
|
Kerek F, Voicu VA. Spherical Oligo-Silicic Acid SOSA Disclosed as Possible Endogenous Digitalis-Like Factor. Front Endocrinol (Lausanne) 2014; 5:233. [PMID: 25667581 PMCID: PMC4304351 DOI: 10.3389/fendo.2014.00233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 12/16/2014] [Indexed: 11/15/2022] Open
Abstract
The Na(+)/K(+)-ATPase is a membrane ion-transporter protein, specifically inhibited by digitalis glycosides used in cardiac therapy. The existence in mammals of some endogenous digitalis-like factors (EDLFs) as presumed ATPase ligands is generally accepted. But the chemical structure of these factors remained elusive because no weighable amounts of pure EDLFs have been isolated. Recent high-resolution crystal structure data of Na(+)/K(+)-ATPase have located the hydrophobic binding pocket of the steroid glycoside ouabain. It remained uncertain if the EDLF are targeting this steroid-receptor or another specific binding site(s). Our recently disclosed spherical oligo-silicic acids (SOSA) fulfill the main criteria to be identified with the presumed EDL factors. SOSA was found as a very potent inhibitor of the Na(+)/K(+)-ATPase, Ca(2+)-ATPase, H(+)/K(+)-ATPase, and of K-dp-ATPase, with IC50 values between 0.2 and 0.5 μg/mL. These findings are even more astonishing while so far, neither monosilicic acid nor its poly-condensed forms have been remarked biologically active. With the diameter ϕ between 1 and 3 nm, SOSA still belong to molecular species definitely smaller than silica nano-particles with ϕ > 5 nm. In SOSA molecules, almost all Si-OH bonds are displayed on the external shell, which facilitates the binding to hydrophilic ATPase domains. SOSA is stable for long term in solution but is sensitive to freeze-drying, which could explain the failure of countless attempts to isolate pure EDLF. There is a strong resemblance between SOSA and vanadates, the previously known general inhibitors of P-type ATPases. SOSA may be generated endogenously by spherical oligomerization of the ubiquitously present monosilicic acid in animal fluids. The structure of SOSA is sensitive to the concentration of Na(+), K(+), Ca(2+), Mg(2+), and other ions suggesting a presumably archaic mechanism for the regulation of the ATPase pumps.
Collapse
Affiliation(s)
- Franz Kerek
- SiNatur GmbH, Martinsried, Germany
- *Correspondence: Franz Kerek, SiNatur GmbH, Am Klopferspitz 19, IZB, 82152 Munich, Germany e-mail:
| | - Victor A. Voicu
- Department of Clinical Pharmacology, Toxicology and Psychopharmacology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| |
Collapse
|
35
|
Ouabain induces endocytosis and degradation of tight junction proteins through ERK1/2-dependent pathways. Exp Cell Res 2014; 320:108-18. [DOI: 10.1016/j.yexcr.2013.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 10/07/2013] [Accepted: 10/09/2013] [Indexed: 11/20/2022]
|
36
|
Morrill GA, Kostellow AB, Gupta RK. A computational analysis of non-genomic plasma membrane progestin binding proteins: signaling through ion channel-linked cell surface receptors. Steroids 2013; 78:1233-44. [PMID: 24012561 DOI: 10.1016/j.steroids.2013.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 08/13/2013] [Accepted: 08/20/2013] [Indexed: 12/18/2022]
Abstract
A number of plasma membrane progestin receptors linked to non-genomic events have been identified. These include: (1) α1-subunit of the Na(+)/K(+)-ATPase (ATP1A1), (2) progestin binding PAQR proteins, (3) membrane progestin receptor alpha (mPRα), (4) progesterone receptor MAPR proteins and (5) the association of nuclear receptor (PRB) with the plasma membrane. This study compares: the pore-lining regions (ion channels), transmembrane (TM) helices, caveolin binding (CB) motifs and leucine-rich repeats (LRRs) of putative progesterone receptors. ATP1A1 contains 10 TM helices (TM-2, 4, 5, 6 and 8 are pores) and 4 CB motifs; whereas PAQR5, PAQR6, PAQR7, PAQRB8 and fish mPRα each contain 8 TM helices (TM-3 is a pore) and 2-4 CB motifs. MAPR proteins contain a single TM helix but lack pore-lining regions and CB motifs. PRB contains one or more TM helices in the steroid binding region, one of which is a pore. ATP1A1, PAQR5/7/8, mPRα, and MAPR-1 contain highly conserved leucine-rich repeats (LRR, common to plant membrane proteins) that are ligand binding sites for ouabain-like steroids associated with LRR kinases. LRR domains are within or overlap TM helices predicted to be ion channels (pore-lining regions), with the variable LRR sequence either at the C-terminus (PAQR and MAPR-1) or within an external loop (ATP1A1). Since ouabain-like steroids are produced by animal cells, our findings suggest that ATP1A1, PAQR5/7/8 and mPRα represent ion channel-linked receptors that respond physiologically to ouabain-like steroids (not progestin) similar to those known to regulate developmental and defense-related processes in plants.
Collapse
Affiliation(s)
- Gene A Morrill
- Department of Physiology & Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
| | | | | |
Collapse
|
37
|
Zandt BJ, Stigen T, Ten Haken B, Netoff T, van Putten MJAM. Single neuron dynamics during experimentally induced anoxic depolarization. J Neurophysiol 2013; 110:1469-75. [PMID: 23825394 DOI: 10.1152/jn.00250.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied single neuron dynamics during anoxic depolarizations, which are often observed in cases of neuronal energy depletion. Anoxic and similar depolarizations play an important role in several pathologies, notably stroke, migraine, and epilepsy. One of the effects of energy depletion was experimentally simulated in slices of rat cortex by blocking the sodium-potassium pumps with ouabain. The membrane voltage of pyramidal cells was measured. Five different kinds of dynamical behavior of the membrane voltage were observed during the resulting depolarizations. Using bifurcation analysis of a single cell model, we show that these voltage dynamics all are responses of the same cell, with normally functioning ion channels, to particular courses of the intra- and extracellular concentrations of sodium and potassium.
Collapse
Affiliation(s)
- Bas-Jan Zandt
- MIRA-Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | | | | | | | | |
Collapse
|
38
|
Crystal structure of the high-affinity Na+K+-ATPase-ouabain complex with Mg2+ bound in the cation binding site. Proc Natl Acad Sci U S A 2013; 110:10958-63. [PMID: 23776223 DOI: 10.1073/pnas.1222308110] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Na(+),K(+)-ATPase maintains electrochemical gradients for Na(+) and K(+) that are critical for animal cells. Cardiotonic steroids (CTSs), widely used in the clinic and recently assigned a role as endogenous regulators of intracellular processes, are highly specific inhibitors of the Na(+),K(+)-ATPase. Here we describe a crystal structure of the phosphorylated pig kidney Na(+),K(+)-ATPase in complex with the CTS representative ouabain, extending to 3.4 Å resolution. The structure provides key details on CTS binding, revealing an extensive hydrogen bonding network formed by the β-surface of the steroid core of ouabain and the side chains of αM1, αM2, and αM6. Furthermore, the structure reveals that cation transport site II is occupied by Mg(2+), and crystallographic studies indicate that Rb(+) and Mn(2+), but not Na(+), bind to this site. Comparison with the low-affinity [K2]E2-MgF(x)-ouabain structure [Ogawa et al. (2009) Proc Natl Acad Sci USA 106(33):13742-13747) shows that the CTS binding pocket of [Mg]E2P allows deep ouabain binding with possible long-range interactions between its polarized five-membered lactone ring and the Mg(2+). K(+) binding at the same site unwinds a turn of αM4, dragging residues Ile318-Val325 toward the cation site and thereby hindering deep ouabain binding. Thus, the structural data establish a basis for the interpretation of the biochemical evidence pointing at direct K(+)-Mg(2+) competition and explain the well-known antagonistic effect of K(+) on CTS binding.
Collapse
|
39
|
Nano-positioning system for structural analysis of functional homomeric proteins in multiple conformations. Structure 2013; 20:1629-40. [PMID: 23063010 DOI: 10.1016/j.str.2012.08.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/01/2012] [Accepted: 08/20/2012] [Indexed: 11/20/2022]
Abstract
Proteins may undergo multiple conformational changes required for their function. One strategy used to estimate target-site positions in unknown structural conformations involves single-pair resonance energy transfer (RET) distance measurements. However, interpretation of inter-residue distances is difficult when applied to three-dimensional structural rearrangements, especially in homomeric systems. We developed a positioning method using inverse trilateration/triangulation to map target sites within a homomeric protein in all defined states, with simultaneous functional recordings. The procedure accounts for probe diffusion to accurately determine the three-dimensional position and confidence region of lanthanide LRET donors attached to a target site (one per subunit), relative to a single fluorescent acceptor placed in a static site. As first application, the method is used to determine the position of a functional voltage-gated potassium channel's voltage sensor. Our results verify the crystal structure relaxed conformation and report on the resting and active conformations for which crystal structures are not available.
Collapse
|
40
|
Pelin M, Boscolo S, Poli M, Sosa S, Tubaro A, Florio C. Characterization of palytoxin binding to HaCaT cells using a monoclonal anti-palytoxin antibody. Mar Drugs 2013; 11:584-98. [PMID: 23442788 PMCID: PMC3705359 DOI: 10.3390/md11030584] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/12/2013] [Accepted: 02/15/2013] [Indexed: 01/14/2023] Open
Abstract
Palytoxin (PLTX) is the reference compound for a group of potent marine biotoxins, for which the molecular target is Na+/K+-ATPase. Indeed, ouabain (OUA), a potent blocker of the pump, is used to inhibit some PLTX effects in vitro. However, in an effort to explain incomplete inhibition of PLTX cytotoxicity, some studies suggest the possibility of two different binding sites on Na+/K+-ATPase. Hence, this study was performed to characterize PLTX binding to intact HaCaT keratinocytes and to investigate the ability of OUA to compete for this binding. PLTX binding to HaCaT cells was demonstrated by immunocytochemical analysis after 10 min exposure. An anti-PLTX monoclonal antibody-based ELISA showed that the binding was saturable and reversible, with a K(d) of 3 × 10-10 M. However, kinetic experiments revealed that PLTX binding dissociation was incomplete, suggesting an additional, OUA-insensitive, PLTX binding site. Competitive experiments suggested that OUA acts as a negative allosteric modulator against high PLTX concentrations (0.3-1.0 × 10-7 M) and possibly as a non-competitive antagonist against low PLTX concentrations (0.1-3.0 × 10-9 M). Antagonism was supported by PLTX cytotoxicity inhibition at OUA concentrations that displaced PLTX binding (1 × 10-5 M). However, this inhibition was incomplete, supporting the existence of both OUA-sensitive and -insensitive PLTX binding sites.
Collapse
Affiliation(s)
- Marco Pelin
- Department of Life Sciences, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy; E-Mails: (M.P.); (S.B.); (S.S.); (C.F.)
| | - Sabrina Boscolo
- Department of Life Sciences, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy; E-Mails: (M.P.); (S.B.); (S.S.); (C.F.)
| | - Mark Poli
- U.S. Army Medical Research Institute of Infectious Diseases, Ft Detrick, MD 21701, USA; E-Mail:
| | - Silvio Sosa
- Department of Life Sciences, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy; E-Mails: (M.P.); (S.B.); (S.S.); (C.F.)
| | - Aurelia Tubaro
- Department of Life Sciences, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy; E-Mails: (M.P.); (S.B.); (S.S.); (C.F.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-040-5588835; Fax: +39-040-5583215
| | - Chiara Florio
- Department of Life Sciences, University of Trieste, Via A. Valerio 6, 34127 Trieste, Italy; E-Mails: (M.P.); (S.B.); (S.S.); (C.F.)
| |
Collapse
|
41
|
Morrill GA, Kostellow AB, Moore RD, Gupta RK. Plasma membrane events associated with the meiotic divisions in the amphibian oocyte: insights into the evolution of insulin transduction systems and cell signaling. BMC DEVELOPMENTAL BIOLOGY 2013; 13:3. [PMID: 23343451 PMCID: PMC3577484 DOI: 10.1186/1471-213x-13-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/22/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Insulin and its plasma membrane receptor constitute an ancient response system critical to cell growth and differentiation. Studies using intact Rana pipiens oocytes have shown that insulin can act at receptors on the oocyte surface to initiate resumption of the first meiotic division. We have reexamined the insulin-induced cascade of electrical and ion transport-related plasma membrane events using both oocytes and intact plasma membranes in order to characterize the insulin receptor-steroid response system associated with the meiotic divisions. RESULTS [(125)I]Insulin binding (K(d) = 54 ± 6 nM) at the oocyte plasma membrane activates membrane serine protease(s), followed by the loss of low affinity ouabain binding sites, with a concomitant 3-4 fold increase in high affinity ouabain binding sites. The changes in protease activity and ouabain binding are associated with increased Na(+)/Ca2(+) exchange, increased endocytosis, decreased Na(+) conductance resulting in membrane hyperpolarization, increased 2-deoxy-D-glucose uptake and a sustained elevation of intracellular pH (pHi). Hyperpolarization is largely due to Na(+)-channel inactivation and is the main driving force for glucose uptake by the oocyte via Na(+)/glucose cotransport. The Na(+) sym- and antiporter systems are driven by the Na(+) free energy gradient generated by Na(+)/K(+)-ATPase. Shifts in α and/or β Na(+)-pump subunits to caveolar (lipid raft) membrane regions may activate Na/K-ATPase and contribute to the Na(+) free energy gradient and the increase in both Na(+)/glucose co-transport and pHi. CONCLUSIONS Under physiological conditions, resumption of meiosis results from the concerted action of insulin and progesterone at the cell membrane. Insulin inactivates Na(+) channels and mobilizes fully functional Na(+)-pumps, generating a Na(+) free energy gradient which serves as the energy source for several membrane anti- and symporter systems.
Collapse
Affiliation(s)
- Gene A Morrill
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Adele B Kostellow
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Richard D Moore
- The Biophysics Laboratory, State University of New York, Plattsburgh, NY, 12901, USA
| | - Raj K Gupta
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| |
Collapse
|
42
|
Morrill GA, Kostellow AB, Askari A. Caveolin-Na/K-ATPase interactions: role of transmembrane topology in non-genomic steroid signal transduction. Steroids 2012; 77:1160-8. [PMID: 22579740 DOI: 10.1016/j.steroids.2012.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/04/2012] [Accepted: 04/10/2012] [Indexed: 12/14/2022]
Abstract
Progesterone and its polar metabolite(s) trigger the meiotic divisions in the amphibian oocyte through a non-genomic signaling system at the plasma membrane. Published site-directed mutagenesis studies of ouabain binding and progesterone-ouabain competition studies indicate that progesterone binds to a 23 amino acid extracellular loop of the plasma membrane α-subunit of Na/K-ATPase. Integral membrane proteins such as caveolins are reported to form Na/K-ATPase-peptide complexes essential for signal transduction. We have characterized the progesterone-induced Na/K-ATPase-caveolin (CAV-1)-steroid 5α-reductase interactions initiating the meiotic divisions. Peptide sequence analysis algorithms indicate that CAV-1 contains two plasma membrane spanning helices, separated by as few as 1-2 amino acid residues at the cell surface. The CAV-1 scaffolding domain, reported to interact with CAV-1 binding (CB) motifs in signaling proteins, overlaps transmembrane (TM) helix 1. The α-subunit of Na/K-ATPase (10 TM helices) contains double CB motifs within TM-1 and TM-10. Steroid 5α-reductase (6 TM helices), an initial step in polar steroid formation, contains CB motifs overlapping TM-1 and TM-6. Computer analysis predicts that interaction between antipathic strands may bring CB motifs and scaffolding domains into close proximity, initiating allostearic changes. Progesterone binding to the α-subunit may thus facilitate CB motif:CAV-1 interaction, which in turn induces helix-helix interaction and generates both a signaling cascade and formation of polar steroids.
Collapse
Affiliation(s)
- Gene A Morrill
- Department of Physiology & Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | | | | |
Collapse
|
43
|
Holden-Dye L, Crisford A, Welz C, von Samson-Himmelstjerna G, Walker RJ, O'Connor V. Worms take to the slo lane: a perspective on the mode of action of emodepside. INVERTEBRATE NEUROSCIENCE : IN 2012; 12:29-36. [PMID: 22539031 PMCID: PMC3360863 DOI: 10.1007/s10158-012-0133-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 04/03/2012] [Indexed: 02/07/2023]
Abstract
The cyclo-octapdepsipeptide anthelmintic emodepside exerts a profound paralysis on parasitic and free-living nematodes. The neuromuscular junction is a significant determinant of this effect. Pharmacological and electrophysiological analyses in the parasitic nematode Ascaris suum have resolved that emodepside elicits a hyperpolarisation of body wall muscle, which is dependent on extracellular calcium and the efflux of potassium ions. The molecular basis for emodepside's action has been investigated in forward genetic screens in the free-living nematode Caenorhabditis elegans. Two screens for emodepside resistance, totalling 20,000 genomes, identified several mutants of slo-1, which encodes a calcium-activated potassium channel homologous to mammalian BK channels. Slo-1 null mutants are more than 1000-fold less sensitive to emodepside than wild-type C. elegans and tissue-specific expression studies show emodepside acts on SLO-1 in neurons regulating feeding and motility as well as acting on SLO-1 in body wall muscle. These genetic data, combined with physiological measurements in C. elegans and the earlier physiological analyses on A. suum, define a pivotal role for SLO-1 in the mode of action of emodepside. Additional signalling pathways have emerged as determinants of emodepside's mode of action through biochemical and hypothesis-driven approaches. Mutant analyses of these pathways suggest a modulatory role for each of them in emodepside's mode of action; however, they impart much more modest changes in the sensitivity to emodepside than mutations in slo-1. Taken together these studies identify SLO-1 as the major determinant of emodepside's anthelmintic activity. Structural information on the BK channels has advanced significantly in the last 2 years. Therefore, we rationalise this possibility by suggesting a model that speculates on the nature of the emodepside pharmacophore within the calcium-activated potassium channels.
Collapse
Affiliation(s)
- Lindy Holden-Dye
- Centre for Biosciences, University of Southampton, Building 85, University Road, Southampton, SO17 1BJ, UK.
| | | | | | | | | | | |
Collapse
|
44
|
Alfonso A, Fernández-Araujo A, Alfonso C, Caramés B, Tobio A, Louzao M, Vieytes M, Botana L. Palytoxin detection and quantification using the fluorescence polarization technique. Anal Biochem 2012; 424:64-70. [DOI: 10.1016/j.ab.2012.02.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 01/19/2012] [Accepted: 02/09/2012] [Indexed: 11/16/2022]
|
45
|
Abstract
Dystonia is a movement disorder characterized by involuntary muscle contractions resulting in abnormal postures. Although common in the clinic, the etiology of dystonia remains unclear. Most dystonias are idiopathic and are not associated with clear pathological brain abnormalities. Attempts to genetically model these dystonias in rodents have failed to replicate dystonic symptoms. This is at odds with the fact that rodents can exhibit dystonia. Because of this discrepancy, it is necessary to consider alternative approaches to generate phenotypically and genotypically faithful models of dystonia. Conditional knockout of dystonia-related genes is 1 technique that may prove useful for modeling genetic dystonias. Lentiviral-mediated small or short hairpin RNA (shRNA) knockdown of particular genes is another approach. Finally, in cases in which the function of a dystonia-related gene is well-known, pharmacological blockade of the protein product can be used. Such an approach was successfully implemented in the case of rapid-onset dystonia parkinsonism, DYT12. This (DYT12) is a hereditary dystonia caused by mutations in the α₃ isoform of the sodium potassium adenosine triphosphatase (ATPase) pump (sodium pump), which partially hampers its physiological function. It was found that partial selective pharmacological block of the sodium pumps in the cerebellum and basal ganglia of mice recapitulates all of the salient features of DYT12, including dystonia and parkinsonism induced by stress. This DYT12 model is unique in that it faithfully replicates human symptoms of DYT12, while targeting the genetic cause of this disorder. Acute disruption of proteins implicated in dystonia may prove a generally fruitful method to model dystonia in rodents.
Collapse
Affiliation(s)
- Rachel Fremont
- Dominic P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461 USA
| | - Kamran Khodakhah
- Dominic P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461 USA
| |
Collapse
|